toxins

We are searching for information regarding toxic analogues of
neuropeptides. What we'd like is compounds that can be used in an
analogous fashion to 6-hydroxydopamine and kainate to kill specific
neurons. We'd like to use such toxic analogues to specifically kill
neurons which respond to such neuropeptides as vasopressin, bombesin, and
FMRFamide for studies of regulation of nerve net development in Hydra
(various subsets of nerves in Hydra use one or more of these three
neuropeptides). Has it been possible to produce such analogues? If so,
references and suppliers names would be greatly appreciated.